Digital cameras and digital photo frames are known as an image display apparatus that reproduces digital image data on a display device such as a liquid crystal display panel. Such an image display apparatus may display a thumbnail display screen, which shows reduced pictures of images recorded as image data files in a storage medium (hereafter called “thumbnails”). The thumbnail display screen enables the user to choose any of the recorded images while browsing their thumbnails. By means of the thumbnails, the user can easily identify the target image even when there are many image data files in the storage medium.
Meanwhile, recent storage media have remarkably increased storage capacity, which makes it possible to store as many as from several hundred to several thousand image data files in one storage medium. With such enormous data volume, screening of image data is difficult even while the thumbnails of stored images are displayed. To cope with this inconvenience, US Patent No. 2007/0076231 (corresponding to JPA 2007-101573) suggests a method that can display thumbnails of limited image data files. In this method, before making image data selection, the user enters a search criterion such as the date of shooting, so that the thumbnails of merely those image data files which match the search criterion are shown up. The search criterion will narrow the search range of image data files to be displayed as thumbnails, so that the user can find the target image data file more easily even while a huge number of image data are stored in a storage medium.
The above-mentioned prior art also has a function of entering two or more search criteria so that those image data files which meet the search criteria will be shown as thumbnails. Where there are a huge number of image data files, a single search criterion can be insufficient to screen the image data files enough; many image data files may remain unscreened. Entering multiple search criteria to display thumbnails of merely those image data files which match the search criteria will achieve more detailed screening of the image data files.
However, using two or more search criteria to narrow the search range may result in excessive screening of the image data, hindering the thumbnails of expected image data files from being displayed. In that case, the user must repeat entering other search criteria in order to get a desired search result that satisfies the user's intention, which will bother the user and reduce efficiency of searching operation.
For this reason, where there are a huge number of image data files in a storage medium, the above prior art is not effective enough to facilitate identifying desired image data files. Therefore, there has been a demand for the image display apparatus to facilitate finding desired image data files.
The present invention is provided to solve the problem above; the object of the present invention is to make it easy to identify such image data files that meet the user's intention, even when a huge number of image data files are stored in a storage medium.